Metal complexes with chelating C-, N-donor ligands for forming metal-containing films

A precursor composition comprising one or more complexes of the formula:

• wherein:
• M is a transition metal;
• each R group is independently H, a hydrocarbyl group, a halogenated hydrocarbyl group, a halide, or a silylated hydrocarbyl group, with the proviso that R3 and R4 are not both H, optionally any of the R groups are joined together to form a ring or rings, and optionally the R groups are replaced by multiple bonds between atoms;
• each L group is independently H, a hydrocarbyl group, a halogenated hydrocarbyl group, a silylated hydrocarbyl group, or a halide;
• x=1 to 3;
• n=0 to 4;
• y=0 to 4;
• and
• further wherein the precursor composition includes at least two complexes containing different metals.